In the art of document handling and processing such as, for example, insertion machines which handle the insertion of bills, promotional materials, or the like, into envelopes prior to dispatch to a customer, it is common for a user of these types of machines separately to purchase from other manufacturers certain auxiliary devices, such as feeders which accumulate, and subsequently dispense into the insertion device, the various inserts to complete the particular package comprised of a particular set of inserts destined for a particular customer. It is not unusual for a particular insertion machine to have a plurality of auxiliary feeders associated therewith, so that a varying plurality of inserts can be inserted into an envelope destined, say, for customers located in a particular zip code area.
As those skilled in the art will know, insertion machines as represented, for example, by the apparatus disclosed in U.S. Pat. No. 4,955,185, assigned to the same assignee as this application, and the disclosure of which is incorporated by reference herein, typically operate repeatedly within a time interval known as a machine cycle. Thus, for example, the various steps performed by an insertion machine are timed to repeatedly occur at certain degrees of a machine cycle (DMC). It is therefore important for any auxiliary device, such as an insert feeder from a manufacturer other than that of the insertion apparatus, to operate at the appropriate degrees of the DMC of the insertion apparatus--the main device--so that inserts are fed by the feeder when the insertion apparatus has a need therefor.
Accordingly, it is a primary object of this invention to synchronize the operation of an auxiliary device attached to a main device to the operational cycle of the main device.
One of the major events within the DMC of insertion apparatus is the establishment of vacuum within the various component parts thereof. This vacuum is used, inter alia, to apply suction to documents so that they can be manipulated, e.g. moved to another station, for subsequent processing. In general, a plurality of such vacuum stations exist in any insertion machine. It is therefore both desireable, and necessary, to establish timely and proper vacuum levels at all points of the insertion device so that vacuum is available when, and as, needed. In practice, this calls for the initiation of vacuum, i.e. the start of air evacuation from various chambers and lines, at a DMC well before the DMC that such, now fully developed, vacuum is needed. In other words, the fluid inertia of the various vacuum circuits of the insertion apparatus has to be accommodated by starting the application of vacuum prior to its actual time of use so that it can develop to the desired levels when the time for its utilization has arrived. Thus, any auxiliary device which times the initiation of its own operational cycle to the start of vacuum application of the main device is likely to be severely premature, hence utterly useless.
Accordingly, it is yet another object of this invention to synchronize the operational cycle of a vacuum responsive auxiliary device attached to an also vacuum responsive main device to the time of actual utilization of vacuum by such main device.
Insertion machines of the type described generally have control logic which also governs the termination of vacuum when, for example, absence of envelopes, or inserts, to be stuffed is indicated. Such might be the case when a mailing to all customers has been completed or when there is an absence of (at least some) inserts that are required for a particular mailing. In such cases, the vacuum that was fully established at a certain DMC is terminated at a subsequent DMC. The control logic of the insertion machine makes the go, no go, decision on maintaining vacuum at some point of the machine cycle after initiation of vacuum but prior to the end of the machine cycle. Any auxiliary device therefore cannot be placed in operation until after the go, no go, decision has been made by the control logic and a continuation of vacuum has been ordered.
Thus, it is another object of the invention to prevent the actuation of a vacuum responsive auxiliary device attached to an also vacuum responsive main device until the main device has maintained vacuum beyond a certain point of its machine cycle.